Heterophyes heterophyes
Encyclopedia
Heterophyes heterophyes is a human parasite.
, Asia Minor
, Korea
, China
, Japan
, Taiwan
, and the Philippines
.
s of fish-eating
bird
s and mammal
s. The eggs are hard to tell apart from other related species so there is no accurate estimate of human infection. The adult flukes range from 1.0mm to 1.7mm long and about 0.35mm at their greatest width. The body of the fluke is covered in scales mostly concentrated at the anterior end. Also at the anterior end is an oral sucker. Located in the medioanterior of the body is the acetabulum
. At the posterior end of the fluke are two oval testes. The vas deferens
leading from the testes expands to form a seminal vesicle
and then narrows again to form an ejaculatory duct
. The fluke also has female reproductive organs. Located medioposterior is the fluke's one ovary and leading away from the ovary
is the vitellaria. The uterus
is a long tube like structure that also leads away from the ovary and joins up with the ejaculatory duct to form the genital duct which leads to a genital sinus. The sinus leads to the genital pore which is lined with 60-90 toothed spines. The genital pore is where the fluke releases its eggs.
but do not hatch until they are ingested by a snail
(Pirenella conica in Egypt
or Cerithidia cingula in Japan
). Inside the snails gut, the miracidium becomes a sporocyst
which then begin to produce rediae. The rediae produce cercariae which then exit the snail, swim toward the surface of the water, and slowly fall back down. On their way down, they contact a fish
and penetrate into the epithelium
of the fish. Here, the cercariae encyst in the muscle tissue. The definitive host, such as humans or birds, eats the undercooked or raw meat of a fish and ingest the parasite.
are those who live by bay waters including fishermen
. Infection is acquired by eating raw fish, a common food in areas of heavy endemicity. In endemic areas, people who live near lake shores or river banks usually have a higher rate and intensity of infection than those living a distance from such areas. It is possible that inhabitants of these areas eat more low-salted or improperly cooked fish and that their fish are obtained from polluted water
. It is common practice for people to defecate
on the lake shores and river banks or from their boats while fishing.
. Sometimes eggs can enter the blood
and lymph vascular systems through mucosa go into the ectopic sites in the body. The heart
can be affected with tissue reaction in the valves
and myocardium that cause heart failure. Eggs can also get into the brain
or spinal cord
and cause neurological disorder
s and sometimes fatalities
.
Geography
Common in north AfricaNorth Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
, Asia Minor
Asia Minor
Asia Minor is a geographical location at the westernmost protrusion of Asia, also called Anatolia, and corresponds to the western two thirds of the Asian part of Turkey...
, Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
, and the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
.
Morphology
Minute teardrop-shaped flukes found in the small intestineSmall intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
s of fish-eating
Piscivore
A piscivore is a carnivorous animal which eats primarily fish. Piscivory was the diet of early tetrapods , insectivory came next, then in time reptiles added herbivory....
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s and mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. The eggs are hard to tell apart from other related species so there is no accurate estimate of human infection. The adult flukes range from 1.0mm to 1.7mm long and about 0.35mm at their greatest width. The body of the fluke is covered in scales mostly concentrated at the anterior end. Also at the anterior end is an oral sucker. Located in the medioanterior of the body is the acetabulum
Acetabulum
The acetabulum is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.-Structure:...
. At the posterior end of the fluke are two oval testes. The vas deferens
Vas deferens
The vas deferens , also called ductus deferens, , is part of the male anatomy of many vertebrates; they transport sperm from the epididymis in anticipation of ejaculation....
leading from the testes expands to form a seminal vesicle
Seminal vesicle
The seminal vesicles or vesicular glands are a pair of simple tubular glands posteroinferior to the urinary bladder of male mammals...
and then narrows again to form an ejaculatory duct
Ejaculatory duct
-Anatomy:The ejaculatory ducts are paired structures in male anatomy. Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and open into the urethra at the Colliculus seminalis...
. The fluke also has female reproductive organs. Located medioposterior is the fluke's one ovary and leading away from the ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
is the vitellaria. The uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
is a long tube like structure that also leads away from the ovary and joins up with the ejaculatory duct to form the genital duct which leads to a genital sinus. The sinus leads to the genital pore which is lined with 60-90 toothed spines. The genital pore is where the fluke releases its eggs.
Biology
The adult flukes live burrowed between the villi of the host's small intestine. The eggs that are laid contain a miracidiumMiracidium
Trematodes are small parasitic flatworms that use vertebrates as their definitive host, and molluscs as their intermediate host. In order to accomplish this, they have several varied lifecyle stages....
but do not hatch until they are ingested by a snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
(Pirenella conica in Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
or Cerithidia cingula in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
). Inside the snails gut, the miracidium becomes a sporocyst
Sporocyst
Sporocyst is a common name of a lifecycle stage in two unrelated groups of species:*Apicomplexa parasites: see Apicomplexa lifecycle stages*Trematode flatworms: see Trematode lifecycle stages...
which then begin to produce rediae. The rediae produce cercariae which then exit the snail, swim toward the surface of the water, and slowly fall back down. On their way down, they contact a fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
and penetrate into the epithelium
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
of the fish. Here, the cercariae encyst in the muscle tissue. The definitive host, such as humans or birds, eats the undercooked or raw meat of a fish and ingest the parasite.
Epidemiology
People at high risk for infectionInfection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
are those who live by bay waters including fishermen
Fisherman
A fisherman or fisher is someone who captures fish and other animals from a body of water, or gathers shellfish. Worldwide, there are about 38 million commercial and subsistence fishermen and fish farmers. The term can also be applied to recreational fishermen and may be used to describe both men...
. Infection is acquired by eating raw fish, a common food in areas of heavy endemicity. In endemic areas, people who live near lake shores or river banks usually have a higher rate and intensity of infection than those living a distance from such areas. It is possible that inhabitants of these areas eat more low-salted or improperly cooked fish and that their fish are obtained from polluted water
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
. It is common practice for people to defecate
Defecation
Defecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...
on the lake shores and river banks or from their boats while fishing.
Pathology
Each worm causes a mild inflammatory reaction at its site of contact with the intestine. In heavy infections which are common cause damage to the mucosa and produce intestinal pain and mucosa diarrheaDiarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
. Sometimes eggs can enter the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
and lymph vascular systems through mucosa go into the ectopic sites in the body. The heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
can be affected with tissue reaction in the valves
Heart valve
A heart valve normally allows blood flow in only one direction through the heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart...
and myocardium that cause heart failure. Eggs can also get into the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
or spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
and cause neurological disorder
Neurological disorder
A neurological disorder is a disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or in the nerves leading to or from them, can result in symptoms such as paralysis, muscle weakness, poor coordination, loss of sensation, seizures,...
s and sometimes fatalities
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
.